Apparatus and method for the electrolytic production of hypochlorous acid

Abstract

An apparatus assembly and method for the electrolytic production of a hypochlorous (HOCl) acid solution are disclosed. A first controlled amount of water, such as tap water, a second controlled amount of an acidic solution (acetic acid or CH 3 COOH), and a third controlled amount of a sodium chloride (NaCl) solution, preferably from a brine solution, are mixed by injecting the same in a reaction loop comprising an electrolytic reactor configured to electrolyze the mixture into the HOCl solution. Preferably, the electrolytic reactor comprises DSA (dimensionally stable anodes). The mixture is circulated in the reaction loop until the HOCl solution is formed. The assembly can be monitored in real-time and remotely for quality control. The disinfecting solution as produced comprises 330-460 ppm HOCl at a pH between 5 and 6, preferably at a pH of 5.5, the solution being stable at least up to 6 months after being produced.

1 ) An apparatus assembly for the electrolytic production of a hypochlorous acid (HOCl) solution from water, an acidic solution and a sodium chloride (NaCl) solution, the apparatus assembly comprising:
 an electrolytic reactor having an electrically powered electrode assembly inside a reaction chamber; and   a loop pump fluidly connected to the reaction chamber such as to form a reaction loop with the electrolytic reactor;   wherein the reaction loop is configured to receive the water, the acidic solution and the sodium chloride solution which are mixed together therein; and   wherein the electrolytic reactor is configured to electrolyze the mixture of water, acidic solution and the sodium chloride solution through the reaction chamber to form the HOCl solution.   
     
     
         2 ) The apparatus assembly of  claim 1 , further comprising a control unit operatively connected to the loop pump for controlling a flow of the mixture circulating in the reaction loop. 
     
     
         3 ) (canceled) 
     
     
         4 ) The apparatus assembly of  claim 1 , wherein the electrolytic reactor is a vertical reactor having the electrode assembly comprising at least one anode and at least one cathode operatively connected to a first electric power supply providing a continuous current to the at least one anode, the vertical reactor having an inlet located adjacent a bottom section of the reaction chamber and an outlet located adjacent a top section of the reaction chamber, the mixture of water, acidic solution and sodium chloride solution circulating from the bottom section to the top section of the reaction chamber. 
     
     
         5 ) The apparatus assembly of  claim 1 , wherein the reaction loop further comprises a loop tank fluidly connected to the inlet and outlet of the reactive chamber, the loop tank being configured in size to contain at least a first controlled amount of water, a second controlled amount of the acidic solution and a third controlled amount of the NaCl solution. 
     
     
         6 ) The apparatus assembly of  claim 5 , further comprising a reactive tank assembly comprising at least one reactive tank fluidly connected to the reaction loop via at least one reactive dosing pump for providing the second controlled amount of acidic solution, the third controlled amount of NaCl solution or a mixture thereof. 
     
     
         7 ) The apparatus assembly of  claim 6 , wherein the reactive tank assembly is fluidly connected to the loop tank of the reaction loop for injecting the second and third controlled amounts of acidic and NaCl solutions in the loop tank. 
     
     
         8 ) (canceled) 
     
     
         9 ) The apparatus assembly of  claim 7 , wherein the reactive tank assembly comprises:
 an acid tank fluidly connected to the reaction loop via an acid dosing pump for providing the second controlled amount of acidic solution; and   a salt tank fluidly connected to the reaction loop via a salt dosing pump for providing the third controlled amount of NaCl solution.   
     
     
         10 ) (canceled) 
     
     
         11 ) The apparatus assembly of  claim 9 , further comprising a pH probe operatively connected to the reaction loop for monitoring a pH of the mixture circulating in the reaction loop permitting assessment of a concentration of HOCl in the HOCl solution. 
     
     
         12 ) (canceled) 
     
     
         13 ) (canceled) 
     
     
         14 ) (canceled) 
     
     
         15 ) (canceled) 
     
     
         16 ) (canceled) 
     
     
         17 ) The apparatus assembly according to  claim 11 ,
 wherein the reaction loop comprises a number N of electrolytic reactors, with N≥2, disposed in a parallel configuration and/or in series, the number N being determined in accordance with a volume of HOCl solution to be produced.   
     
     
         18 ) The apparatus assembly of  claim 17 , wherein the electrode assembly of the electrolytic reactor comprises at least one dimensionally stable anode (DSA). 
     
     
         19 ) A method for the electrolytic production of a hypochlorous acid (HOCl) solution from water, an acidic solution and a sodium chloride (NaCl) solution, comprising:
 mixing a first controlled amount of water, a second controlled amount of the acidic solution and a third controlled amount of the sodium chloride (NaCl) solution by injecting the same in a reaction loop comprising an electrolytic reactor configured to electrolyze the mixture into the HOCl solution; and   circulating the mixture in the reaction loop and the electrolytic reactor where the HOCl solution is formed.   
     
     
         20 ) The method of  claim 19 , further comprising controllably activating, by a control unit, one or more pumps for mixing the first, second and third controlled amounts. 
     
     
         21 ) The method of  claim 20 , further comprising mixing the second controlled amount of the acidic solution and a third controlled amount of the sodium chloride (NaCl) solution before injecting the same in the reaction loop. 
     
     
         22 ) The method of  claim 21 , further comprising measuring a pH of the mixture circulating in the reaction loop. 
     
     
         23 ) (canceled) 
     
     
         24 ) The method of  claim 19 , further comprising stopping the circulation of the mixture in the reaction loop when a given concentration of HOCl has been reached. 
     
     
         25 ) The method of  claim 24 , wherein the given concentration of HOCl is obtained at a pH between 5 and 7. 
     
     
         26 ) (canceled) 
     
     
         27 ) The method of  claim 25 , wherein the acidic solution comprises acetic acid (CH 3 COOH). 
     
     
         28 ) The method of  claim 27 , wherein the controlled amount of acidic solution comprises from to 2 to 10 ml of a 10% acetic acid solution per liter of water in the reaction loop. 
     
     
         29 ) (canceled) 
     
     
         30 ) The method of  claim 29 , wherein the third controlled amount of NaCl solution is obtained from a brine solution for providing an equivalent of from 2 to 8 g of NaCl per liter of water in the reaction loop. 
     
     
         31 ) The method of  claim 30 , wherein the brine solution provides an equivalent of about 5 g of NaCl per liter of water in the reaction loop. 
     
     
         32 ) (canceled) 
     
     
         33 ) (canceled) 
     
     
         34 ) (canceled) 
     
     
         35 ) A disinfecting solution comprising the HOCl solution produced with the apparatus assembly as claimed in  claim 1  or by the method as claimed in  claim 19 , wherein the disinfecting solution when produced comprises 330-460 ppm HOCl at a pH between 5 and 6, the solution being stable at least up to 6 months after being produced.